Difference between revisions of "Frequently asked questions about GEOS-Chem"

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On this page we shall answer some commonly asked questions about GEOS-Chem.
 
On this page we shall answer some commonly asked questions about GEOS-Chem.
  
== Basic information about GEOS-Chem ==
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== For new users ==
  
=== For new users ===
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* [https://geos-chem.seas.harvard.edu/welcome.html I am a GEOS-Chem new user.  What is expected of me?]
 
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* [https://geos-chem.readthedocs.io/en/latest/geos-chem-shared-docs/supplemental-guides/related-docs.html Where can I find user manuals for GEOS-Chem and related software?]
* [[GEOS-Chem welcome letter for new users|I am a GEOS-Chem new user.  What is expected of me?]]
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* [[Minimum system requirements for GEOS-Chem|On what types of machines can I run GEOS-Chem?]]
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* [http://cloud.geos-chem.org Can I use GEOS-Chem on cloud-computing platforms?]
 
* [http://cloud.geos-chem.org Can I use GEOS-Chem on cloud-computing platforms?]
* [[Species in GEOS-Chem|What types of simulations can I run with GEOS-Chem?]]
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* [[Guide to GEOS-Chem simulations|What types of simulations can I run with GEOS-Chem?]]
 
* What is the [[GEOS-Chem horizontal grids|horizontal resolution]] and [[GEOS-Chem vertical grids|vertical resolution]] of GEOS-Chem?
 
* What is the [[GEOS-Chem horizontal grids|horizontal resolution]] and [[GEOS-Chem vertical grids|vertical resolution]] of GEOS-Chem?
 
* [[Overview of GMAO met data products|Which meteorological data fields can be used by GEOS-Chem?]]
 
* [[Overview of GMAO met data products|Which meteorological data fields can be used by GEOS-Chem?]]
* [[Submitting GEOS-Chem support requests|To whom can I direct GEOS-Chem-related questions?]]
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* [https://geos-chem.readthedocs.io/en/latest/help-and-reference/SUPPORT.html To whom may I direct GEOS-Chem-related questions?]
* [http://acmg.seas.harvard.edu/geos/geos_steering_cmte.html What does the GEOS-Chem Steering Committee do?]
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* [https://geoschem.github.io/steering-cmte.html What does the GEOS-Chem Steering Committee do?]
* [http://acmg.seas.harvard.edu/geos/geos_working_groups.html What do the GEOS-Chem Working Groups do?]
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* [https://geoschem.github.io/working-groups.html What do the GEOS-Chem Working Groups do?]
* [[GEOS-Chem Support Team|What does the GEOS-Chem Support Team do?]]
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* [https://geoschem.github.io/support-team What does the GEOS-Chem Support Team do?]
* [[Subscribing_to_the_GEOS-Chem_email_lists|I see that there are several GEOS-Chem email lists.  How can I subscribe?]]
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* [https://geoschem.github.io/email-lists I see that there are several GEOS-Chem email lists.  How can I subscribe?]
  
--[[User:Bmy|Bob Yantosca]] ([[User talk:Bmy|talk]]) 17:45, 2 January 2019 (UTC)
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== Science questions ==
 
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=== Science questions ===
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Where can I find information about ...
 
Where can I find information about ...
  
* [[GEOS-Chem chemistry mechanisms|the available chemical mechanisms in GEOS-Chem?]]
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* [[Guide to GEOS-Chem simulations|types of GEOS-Chem simulations that I can run?]]
* [[Bromine chemistry mechanism|the bromine chemistry mechanism in GEOS-Chem?]]
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* [[Bromine chemistry mechanism|bromine chemistry?]]
* [[FlexChem|the KPP chemical solver?]]
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* [https://kpp.readthedocs.io The chemical solver used in GEOS-Chem?]
 
* [[Linoz stratospheric ozone chemistry|the Linoz stratospheric ozone chemistry scheme?]]
 
* [[Linoz stratospheric ozone chemistry|the Linoz stratospheric ozone chemistry scheme?]]
* [[GEOS-Chem_chemistry_mechanisms#Stratospheric_chemistry|the stratospheric chemistry mechanism?]]
 
* [[Offline chemistry simulations|Other chemistry simulations such as CO2, CH4, Hg, etc.?]]
 
* [[HEMCO data directories|emissions options in GEOS-Chem?]]
 
 
* [[Advection scheme TPCORE|the advection scheme in GEOS-Chem?]]
 
* [[Advection scheme TPCORE|the advection scheme in GEOS-Chem?]]
 
* [[Boundary layer mixing|the boundary layer mixing schemes in GEOS-Chem?]]
 
* [[Boundary layer mixing|the boundary layer mixing schemes in GEOS-Chem?]]
 
* [[Cloud convection|the cloud convection schemes in GEOS-Chem?]]
 
* [[Cloud convection|the cloud convection schemes in GEOS-Chem?]]
 
* The [[Dry deposition]] and [[Wet deposition]] schemes in GEOS-Chem?
 
* The [[Dry deposition]] and [[Wet deposition]] schemes in GEOS-Chem?
* [[GEOS-Chem nested grid simulations]]?
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* [https://geos-chem.readthedocs.io/en/latest/supplemental-guides/nested-grid-guide.html GEOS-Chem nested grid simulations]?
  
--[[User:Bmy|Bob Yantosca]] ([[User talk:Bmy|talk]]) 17:45, 2 January 2019 (UTC)
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== Technical issues ==
  
=== Technical issues ===
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* [https://geos-chem.readthedocs.io/en/latest/gcclassic-user-guide/get-code.html How do I download the GEOS-Chem source code]
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* [https://geos-chem.readthedocs.io/en/latest/gcclassic-user-guide/create-rundir.html How do I create run directories?]
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* [https://geos-chem.readthedocs.io/en/latest/geos-chem-shared-docs/supplemental-guides/error-guide.html What should I do when I encounter an error while running GEOS-Chem]?
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* [https://github.com/geoschem/geos-chem/issues Is there a comprehensive list of GEOS-Chem bug reports?]
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* Do you have any information on how I can [https://geos-chem.readthedocs.io/en/latest/geos-chem-shared-docs/supplemental-guides/debug-guide.html debug GEOS-Chem or HEMCO errors]?
  
* [[Using Git with GEOS-Chem#Downloading a new GEOS-Chem version|How do I download the GEOS-Chem source code and run directories?]]
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== Parallelization issues ==
* [[Common GEOS-Chem error messages|What should I do when I encounter an error while running GEOS-Chem]]?
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* [https://geos-chem.readthedocs.io/en/latest/geos-chem-shared-docs/supplemental-guides/parallel-guide.html#how-can-i-tell-what-should-go-into-the-omp-private-clause How can I tell if a variable has to be declared with <tt>!$OMP PRIVATE</tt> or <tt>!$OMP SHARED?</tt>]
* Do you have any information about [[Guide to GEOS-Chem performance|GEOS-Chem performance]] and [[GEOS-Chem scalability]]?
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* [https://geos-chem.readthedocs.io/en/latest/geos-chem-shared-docs/supplemental-guides/parallel-guide.html#how-many-cores-may-i-use-for-geos-chem-or-hemco How many CPU cores may I use for my GEOS-Chem Classic simulation?]
* [[GEOS-Chem Makefile Structure|Where can I learn more about the GEOS-Chem Makefiles?]]
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* [https://geos-chem.readthedocs.io/en/latest/geos-chem-shared-docs/supplemental-guides/parallel-guide.html#why-is-geos-chem-is-not-using-all-the-cores-i-requested Why is GEOS-Chem Classic not using all the CPU cores that I requested?]
* [[Bugs and fixes|Is there a comprehensive list of GEOS-Chem bugs and how they were fixed?]]
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* [[GEOS-Chem basics|I am new to programming. Do you have any online resources or tutorials?]]
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* Are there any [[Floating point math issues|numerical issues]] that I should be aware of?
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* Do you have any tools that would help me [[Debugging with the GEOS-Chem unit tester|debug GEOS-Chem more efficiently?]]
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--[[User:Bmy|Bob Yantosca]] ([[User talk:Bmy|talk]]) 17:45, 2 January 2019 (UTC)
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== High-Performance GEOS-Chem (GCHP) ==
  
=== Parallelization issues ===
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Please see the GCHP user manual at [https://gchp.readthedocs.io <tt>gchp.readthedocs.io</tt>]for more information.
* [[Parallelizing_GEOS-Chem#How_can_I_tell_if_a_variable_has_to_be_declared_with_PRIVATE_or_SHARED.3F|How can I tell if a variable has to be declared with <tt>!$OMP PRIVATE</tt> or <tt>!$OMP SHARED?</tt>]]
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* [[Parallelizing_GEOS-Chem#How_many_CPUs_may_I_use_in_my_GEOS-Chem_simulation.3F|How many CPUs may I use for my GEOS-Chem simulation?]]
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* [[Parallelizing_GEOS-Chem#Why_is_GEOS-Chem_is_not_using_all_the_CPUs_I_requested.3F|Why is GEOS-Chem not using all the CPUs that I requested?]]
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--[[User:Bmy|Bob Yantosca]] ([[User talk:Bmy|talk]]) 17:45, 2 January 2019 (UTC)
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=== High-Performance GEOS-Chem (GCHP) ===
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Please see the [[GCHP_Main_Page|GCHP main wiki page]] for information about GCHP.
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== Where can I get restart files for GEOS-Chem? ==
 
== Where can I get restart files for GEOS-Chem? ==
  
For instructions on how to obtain a set of sample restart files that you can use to spin up your own simulations, please see [[GEOS-Chem_basics#Restart_files|the ''Restart Files'' section of our ''GEOS-Chem basics'' wiki page]].
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For instructions on how to obtain a set of sample restart files that you can use to spin up your own simulations, [https://geos-chem.readthedocs.io/en/latest/gcclassic-user-guide/restart-files-gc.html#where-can-i-get-a-restart-file-for-my-simulation please visit this link].
 
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--[[User:Bmy|Bob Yantosca]] ([[User talk:Bmy|talk]]) 16:24, 6 January 2017 (UTC)
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== Running GEOS-Chem ==
 
== Running GEOS-Chem ==
  
Please see our ''[[Running GEOS-Chem]]'' wiki page.
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Please see the [https://geos-chem.readthedocs.io/en/latest/gcclassic-user-guide/run.html Run your simulation] section of [https://geos-chem.readthedocs.io <tt>geos-chem.readthedocs.io.</tt>]. for more information.
 
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=== How long does GEOS-Chem take to run? ===
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It depends on your particular computing environment.  We have posted several timing results from GEOS-Chem [[GEOS-Chem 7-day timing tests|7-day time test simulations]].
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=== GEOS-Chem seems to be running too slowly.  What can I do? ===
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You should be aware of [[GEOS-Chem Makefile Structure#Compile-time options that can slow down GEOS-Chem|several compile-time options that will slow down GEOS-Chem]]. Use these options only for debugging, but not in your production runs.
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If you are archiving many diagnostic quantities are a high temporal resolution (e.g. every hour), then this will increase the run time of your simulation. You can try saving out less diagnostic quantities, or archiving at a lower temporal resolution (e.g. every day).
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== GEOS-Chem errors ==
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Please also see our ''[[Guide to GEOS-Chem error messages]]'' and ''[[Debugging GEOS-Chem]]'' pages.
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=== GEOS-Chem died with an error.  What can I do? ===
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Please see ''[[Understanding the different categories of errors]]'' section of our ''[[Guide to GEOS-Chem error messages]]''.
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--[[User:Bmy|Bob Yantosca]] ([[User talk:Bmy|talk]]) 14:40, 17 June 2019 (UTC)
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There are several ways to [https://geos-chem.readthedocs.io/en/latest/gcc-guide/05-run/run-speedup.html speed up a slow GEOS-Chem simulation].  If you are archiving many diagnostic quantities are a high temporal resolution (e.g. every hour), then this will increase the run time of your simulation.  You can try saving out less diagnostic quantities, or archiving at a lower temporal resolution (e.g. every day).

Latest revision as of 17:02, 23 May 2024

On this page we shall answer some commonly asked questions about GEOS-Chem.

For new users

Science questions

Where can I find information about ...

Technical issues

Parallelization issues

High-Performance GEOS-Chem (GCHP)

Please see the GCHP user manual at gchp.readthedocs.iofor more information.

Where can I get restart files for GEOS-Chem?

For instructions on how to obtain a set of sample restart files that you can use to spin up your own simulations, please visit this link.

Running GEOS-Chem

Please see the Run your simulation section of geos-chem.readthedocs.io.. for more information.

There are several ways to speed up a slow GEOS-Chem simulation. If you are archiving many diagnostic quantities are a high temporal resolution (e.g. every hour), then this will increase the run time of your simulation. You can try saving out less diagnostic quantities, or archiving at a lower temporal resolution (e.g. every day).